US20070191501A1 - Polystyrene Processing Apparatus and Method - Google Patents
Polystyrene Processing Apparatus and Method Download PDFInfo
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- US20070191501A1 US20070191501A1 US11/458,038 US45803806A US2007191501A1 US 20070191501 A1 US20070191501 A1 US 20070191501A1 US 45803806 A US45803806 A US 45803806A US 2007191501 A1 US2007191501 A1 US 2007191501A1
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- polystyrene
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J11/00—Recovery or working-up of waste materials
- C08J11/04—Recovery or working-up of waste materials of polymers
- C08J11/06—Recovery or working-up of waste materials of polymers without chemical reactions
- C08J11/08—Recovery or working-up of waste materials of polymers without chemical reactions using selective solvents for polymer components
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2325/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Derivatives of such polymers
- C08J2325/02—Homopolymers or copolymers of hydrocarbons
- C08J2325/04—Homopolymers or copolymers of styrene
- C08J2325/06—Polystyrene
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/62—Plastics recycling; Rubber recycling
Definitions
- the invention is an apparatus and method for efficient processing of polystyrene (e.g., discarded expanded or foam polystyrene).
- polystyrene e.g., discarded expanded or foam polystyrene
- Waste polystyrene such as expanded polystyrene
- the density of expanded polystyrene is such that carrying waste expanded polystyrene on trucks is very wasteful. More specifically, expanded polystyrene has such a low density, and hence high relative volume per unit mass, that trucks used to transport waste expanded polystyrene often “bulk out”. In other words, trucks, semi-trucks, tractor-trailers, large rigs, 18-wheeler rigs, etc., can each be filled with expanded polystyrene without any reaching their load carry capacity.
- waste expanded polystyrene takes up a disproportionate amount of space at landfill sites. Recycling expanded polystyrene is economically wasteful in light of the “top out” problem.
- U.S. Pat. No. 6,098,649 issued Aug. 8, 2000 to Aug. 8, 2000, describes a waste recovery system using this apparatus and a liquid container ideal for use with the waste processing apparatus and waste recovery system.
- the waste processing apparatus comprises a processing part for processing supplied waste (for example foam polystyrene) with a processing liquid (for example limonene) and a storing part for storing produced liquid (for example limonene containing dissolved foam polystyrene) produced in this processing part and provided with a removable liquid container constructed to both supply processing liquid to the processing part and receive produced liquid produced by the waste processing apparatus.
- the liquid container is removed from the waste processing apparatus after receiving the produced liquid and carried to a waste recycling apparatus, the produced liquid is transferred from the liquid container into the waste recycling apparatus, waste or waste and processing liquid is recovered from the produced liquid by the waste recycling apparatus and the empty liquid container is filled with new or recycled processing liquid and returned to the waste processing apparatus again.
- a method and apparatus for processing polystyrene includes the steps of: receiving a solution in the form of polystyrene polymer dissolved in an organic solvent; and separating the polystyrene from the solvent by applying heat to the solution to provide a heated solution and then spraying the heated solution to separate the polystyrene from the solvent.
- the apparatus includes: a holding tank at least partly filled with a solution of polystyrene dissolved in an organic solvent; at least one heat exchanger ( 170 ); and a separator in the form of a sprayer unit.
- FIG. 1 is a processing flow diagram of a polystyrene processing apparatus according to an embodiment of the present invention.
- FIG. 2 shows a further process layout according to the invention.
- FIG. 3 shows a schematic diagram of how polystyrene and a solvent such as d-limonene is mixed and filtered prior to heating by a heat exchanger.
- the invention is directed to an apparatus and method for efficient processing of polystyrene (e.g., expanded or foam polystyrene).
- polystyrene e.g., expanded or foam polystyrene
- the apparatus of the present invention is denoted generally by the numeric label 100 .
- FIG. 1 is a processing flow diagram of a polystyrene processing apparatus 100 according to an embodiment of the present invention.
- Polystyrene such as expanded polystyrene
- solvent is held in resin/solvent tank 120 from which it is directed through a particle remover 140 to remove solids to provide a substantially solid free solution of polystyrene and solvent.
- the substantially solid free solution of polystyrene and solvent is thence directed to at least one heat exchanger 170 by operation of a pump 180 .
- the heat exchanger 170 heats up the substantially solid free solution of polystyrene, which is then directed to sprayer 200 .
- the sprayer 200 is located inside a chamber 220 .
- the chamber 220 includes a heating jacket 240 .
- At least one heater 260 is used to provide heated liquid or steam to heating jacket 240 under the operation of at least one pump 270 .
- the amount of heat delivered to the bottom 240 b of the heating jacket 240 should be adjusted to prevent the separated polystyrene polymer from becoming too viscous for efficient plant operation in the bottom part 220 b of chamber 220 .
- a temperature of about 370° F. maintained in the bottom part 240 b of the heating jacket 240 might be sufficient, but it will be understood by a person or ordinary skill in the art that the temperature of the bottom 240 b of heating jacket 240 (and, therefore 220 b ) may vary according to the particular set-up and configuration of the chamber 220 and a person of ordinary skill in the art could establish by routine operation of the plant what temperature should be applied to the bottom 240 b of the heating jacket 240 .
- the temperature of in the vicinity of an at least one spray nozzle 205 can be adjusted to ensure that the solution (polystyrene/solvent) is atomized to a sufficient degree to allow for efficient separation of the polymer from the solvent through evaporation of droplets 210 .
- a filter such as glass wool filter 305 , can be located at the top of chamber 220 near an output port 310 to prevent strands of styrene carrying over from the styrene-polymer/solvent into the heat exchanger 340 .
- the chamber 220 is used to separate the dissolved polystyrene from the solvent.
- a vacuum pump 320 is used to lower the pressure inside chamber 220 .
- the vacuum pump 320 can be a liquid ring vacuum pump to allow the solvent to be moved while maintaining a vacuum.
- the sprayer 200 generates droplets 210 of polystyrene dissolved in solvent, which are directed downward.
- the solvent evaporates from the droplets 210 and is drawn upwards by operation of vacuum pump 320 .
- the solvent is then cooled by heat exchanger 340 , then by heat exchanger 350 (with the vacuum pump 320 located between heat exchangers 340 and 350 ).
- Solvent is collected in a solvent recovery tank 360 .
- the chamber 220 is under a vacuum during operation.
- the vacuum pressure and nozzle pressure can vary and still provide satisfactory operation. More particularly, the vacuum pressure in chamber 220 and nozzle 205 pressure may vary depending based on such factors as heat in the chamber 220 (residual or maintained), GPM or nozzle volume throughput, pressure of produce and laminar flow at nozzles 205 , vacuum separation inherent of atomization based on Newton fall.
- a vacuum of 18′′ Hg (eighteen inches Mercury pressure) in chamber 220 should be sufficient to maintain satisfactory operation, but the vacuum pressure in chamber 220 can vary between about 10′′ Hg and about 29′′ Hg vacuum pressure.
- Nozzle 205 pressure of about 77 PSI (77 pounds pressure per square inch) should provide satisfactory operation, but the nozzle pressure can vary between about 12 PSI and about 85 PSI.
- Recovered solvent held in tank 360 can be reused to dissolve unprocessed polystyrene.
- the polymer is optionally agitated by an agitation section 380 prior to exiting at 400 .
- a sufficient amount of heat is delivered to the heating jacket 240 to maintain a temperature of about 370° F. at the bottom of the chamber 220 to prevent the separated styrene polymer from becoming too viscous and difficult to handle.
- the separated styrene polymer can be converted into pellets by a pelletizer (not shown) as described in U.S. Pat. No. 6,169,121, issued Jan. 2, 2001 to Noguchi et al.
- members such as member 170 (i.e., heat exchanger 170 ) might comprise a single unit (i.e., one heat exchanger 170 ) or operate in parallel to increase or meet throughput requirements.
- member 170 i.e., heat exchanger 170
- FIG. 1 the process and apparatus shown in FIG. 1 can vary in number, rated throughput or rearranged (e.g., in units operating in parallel) and still remain within the scope of the claimed invention.
- a heater 280 is used to provide heat transfer medium to the heat exchanger 170 under the operation of pump 300 .
- the heat transfer medium can take any suitable form such as liquid or gas (e.g., steam). It will be understood by persons of ordinary skill in the art that the various elements shown in FIG. 1 can be arranged differently without detracting from the spirit of the invention. For example, heaters 260 and 280 can be replaced with a single heater without detracting from the spirit of the invention.
- the Applicant has devoted a considerable amount of effort into solving the problem of separating polystyrene polymer from resin-solvent solution by means of vacuum spray drying.
- the resin-solvent solution is extremely viscous and difficult to heat uniformly in a heat exchanger.
- Polystyrene-solvent ratios of 30/70 i.e., 30% polystyrene resin concentration
- the resin tends to stick to heat transfer surfaces thereby deleteriously impacting on heat transfer.
- Resin-solvent ratios of 30/70 are difficult to heat up using, for example, steam heated tube or multiple tube heat exchangers.
- the Applicant makes use of a heat exchanger 170 in combination with sprayer 200 and vacuum pump 320 , wherein the heat exchanger 170 enables rapid uniform heating of the polystyrene/solvent liquid and the sprayer 200 produces droplets with surface area favorable for more rapid conversion of the solvent into gas and hence speaks to a more rapid separation of polystyrene from the solvent leading to increased throughput of polystyrene/solvent.
- the combination of sprayer 200 (especially with twister type nozzles, see later) in combination with the heat exchanger 170 enables separation of the polystyrene/solvent mix without boiling the solvent off as required in the prior art '121 patent.
- the process of the present invention is far more efficient than that of the prior art as disclosed, for example, in the prior art '121 patent.
- the solvent i.e., processing liquid for dissolving polystyrene such as expanded polystyrene dissolved in a solution of solvent such as d-limonene at, for example, about 30% concentration, i.e., a 30/70 polystyrene/solvent solution, respectively
- limonene and more specifically d-limonene is particularly suited as a solvent for dissolving expanded polystyrene to provide a polystyrene/solvent solution.
- the solvent can be at least one solvent chosen from a group consisting of an aromatic organic solvent, a hydrocarbon organic solvent, an ether organic solvent, an ester organic solvent, a ketone organic solvent and a monoterpene organic solvent.
- the solvent can be at least one solvent chosen from the group consisting of limonene, isoamyl acetate, benzyl propionate and ethyl butyrate.
- the solvent can be at least one solvent chosen from the group consisting of d-limonene, isoamyl acetate, benzyl propionate and ethyl butyrate.
- the solvent can be d-limonene.
- the temperature range of operation for the heat exchanger 170 is typically chosen to deliver the solution (i.e., polymer/solvent) at the sprayer 200 in the range between about 235° F. and 255° F.
- a person of ordinary skill in the art would monitor the temperature of the solution entering the sprayer and adjust the heater 280 to ensure the temperature of the solution leaving the heat exchanger 170 is high enough to ensure that the temperature of the fluid entering the sprayer 200 is in the range between about 235° F. and 255° F. It is preferred that the solution is not heated above about 350° F. Expanded polystyrene is sometimes pre-treated with a bromine-based fire retardant, which can cause problems if the solution is heated above about 350° F.
- the sprayer 200 should be capable of atomizing the solution to ensure rapid evaporation of the solvent and hence separation of the polystyrene from the solvent.
- the sprayer 200 makes use of at least one nozzle 205 . Any suitable nozzle can be used so long as the nozzle atomizes the solution, i.e., produces a stream of droplets 210 sufficiently small to allow rapid evaporation of the solvent.
- the at least one nozzle 205 can produce, for example, a hollow coned spray, a full coned spray or a flat spray.
- the at least one nozzle 205 can be at least one nozzle chosen from a group consisting of a hollow coned spray nozzle, a full coned spray nozzle, a flat spray nozzle, and a twister nozzle.
- twister nozzle An example of a twister nozzle is the YS series twister nozzle supplied by BEX Incorporated (located at various sites including: 37709 Schoolcraft Road, Livonia, Mich., 48150-1009 USA). BEX Inc. also provides a wide selection of hollow coned, full coned and flat spray nozzles.
- Spraying Systems Company also provide a range of spraying system nozzles such as, but not limited to, a full jet, 3 ⁇ 8′′, 316SS with a 22 drill (Part # 3/8HH-316SS22). Spraying Systems Company can be contacted at: PO Box 7900, Wheaton Ill. 60189-7900, Phone 630-665-5000. A suitable nozzle type is described in U.S. Pat. No. 3,104,829 issued Sep. 24, 1963 to Wahlin. In addition, Spray Systems Company provides a new range of stainless steel IceJetTM inlet cooling and evaporation nozzles. The IceJetTM inlet cooling and evaporation nozzle utilizes a whirl chamber to produce a fine mist of droplets.
- FIG. 2 shows a further process layout according to the invention.
- FIG. 3 shows a schematic diagram of how polystyrene and a solvent such as d-limonene is mixed and filtered prior to heating by heat exchanger 170 .
- Example ranges of polystyrene concentration (as volume %) with respect to d-limonene are provided. Specifically, the example range is 1/99 (where the d-limonene solvent contains 1 volume % polystyrene) to 60/40 (where d-limonene solvent contains 60 volume % polystyrene). It will be understood that the exact way of mixing can vary without detracting from the spirit of the claimed invention.
- the bottom 240 b of the heating jacket 240 is configured to function, at least partly, as a porous heated plate.
- the heating jacket 240 is a basic round vessel that is approximately 1 ⁇ 2 inch thick (variable based on throughput) and has oil circulating in between 2-10 gauge plates at the bottom end 240 b , which is also angled inwards and has, for example, multiple 1 ⁇ 2 inch openings with oil caused to flow around them. The angle is in relation so that molten polystyrene will flow through into the bottom of the vessel without allowing the mist (originating from droplets 210 ) to go straight through.
- this heated and angled bottom part 240 b with holes is to allow the polystyrene to flatten and thereby increase surface area then flow into the bottom 220 b of vessel 220 .
- the temperature at the bottom 240 b can be in the range 350° F. to 375° F.
- the upper part of the chamber 220 is maintained at about 390° F.
- Example #1 the solution (of polystyrene/solvent) enters #22 nozzle at 60-80 psi in (larger than needed 3.4 GPM @1800cP) but there is a possibility of a stringing effect (due to the larger orifice) up to 165° F. in a 70/30 (solvent/polystyrene) ratio and stringing or sporadic effect up to 180° F. due to possible laminar flow and centipoises value of the mass.
- At the least one spray nozzle 205 (if d-limonene solvent is used, 235° F. is about 15° F. degrees above boiling point of the solvent).
- 235° F. is about 15° F. degrees above boiling point of the solvent.
- Some atomizing effect might be lost because of substance consistency but the height of the vessel and substance velocity should be large enough that any un-flashed solvent will loosen from entrainment through the product/chamber vessel 220 temperature being high enough to create vapor pressure greater than the polymer entrainment ability.
- the Newton force is pulling on the mass (polystyrene) not on the vapor (unless entrained), hence the use of the porous heated section 240 b (any entrained vapor will be released upon impact with 240 b ).
- blast plate 240 b It is preferred, but not totally necessary, that no more than about 5% of vapors are recovered at blast plate 240 b . It should be understood that the terms “blast base plate 240 b ” and “bottom 240 b of the heating jacket 240 ” are regarded in this embodiment as equivalent terms.
Abstract
Description
- This application claims the benefit of priority from U.S. Provisional Patent Application Ser. No. 60/773,664, filed Feb. 16, 2006, the entire contents of which is incorporated herein by reference.
- Not Applicable.
- The invention is an apparatus and method for efficient processing of polystyrene (e.g., discarded expanded or foam polystyrene).
- Waste polystyrene, such as expanded polystyrene, presents particular economic and environmental problems. The density of expanded polystyrene is such that carrying waste expanded polystyrene on trucks is very wasteful. More specifically, expanded polystyrene has such a low density, and hence high relative volume per unit mass, that trucks used to transport waste expanded polystyrene often “bulk out”. In other words, trucks, semi-trucks, tractor-trailers, large rigs, 18-wheeler rigs, etc., can each be filled with expanded polystyrene without any reaching their load carry capacity.
- In addition, the environmental impact of waste expanded polystyrene is a serious matter. Waste expanded polystyrene takes up a disproportionate amount of space at landfill sites. Recycling expanded polystyrene is economically wasteful in light of the “top out” problem.
- There are several issued U.S. Patents devoted to dealing with the economic and environmental issues surrounding the burying or recycling of waste expanded polystyrene, such as U.S. Pat. No. 6,169,121, issued Jan. 2, 2001 to Noguchi et al. The '121 patent describes a processing method for effectively and promptly removing insoluble components contained in a solution of a styrene resin waste material to enable regeneration of high-quality regenerated styrene. A solution of the styrene resin waste material in an organic solvent is processed with, for example, a dehydrating agent, to remove insoluble components. The resulting clarified solution is degasified on heating in vacuum to remove the organic solvent for recycling the resulting mass as a regenerated styrene resin.
- U.S. Pat. No. 6,098,649, issued Aug. 8, 2000 to Aug. 8, 2000, describes a waste recovery system using this apparatus and a liquid container ideal for use with the waste processing apparatus and waste recovery system. The waste processing apparatus comprises a processing part for processing supplied waste (for example foam polystyrene) with a processing liquid (for example limonene) and a storing part for storing produced liquid (for example limonene containing dissolved foam polystyrene) produced in this processing part and provided with a removable liquid container constructed to both supply processing liquid to the processing part and receive produced liquid produced by the waste processing apparatus. In the waste recovery system, the liquid container is removed from the waste processing apparatus after receiving the produced liquid and carried to a waste recycling apparatus, the produced liquid is transferred from the liquid container into the waste recycling apparatus, waste or waste and processing liquid is recovered from the produced liquid by the waste recycling apparatus and the empty liquid container is filled with new or recycled processing liquid and returned to the waste processing apparatus again.
- A method and apparatus for processing polystyrene. The method includes the steps of: receiving a solution in the form of polystyrene polymer dissolved in an organic solvent; and separating the polystyrene from the solvent by applying heat to the solution to provide a heated solution and then spraying the heated solution to separate the polystyrene from the solvent. The apparatus includes: a holding tank at least partly filled with a solution of polystyrene dissolved in an organic solvent; at least one heat exchanger (170); and a separator in the form of a sprayer unit.
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FIG. 1 is a processing flow diagram of a polystyrene processing apparatus according to an embodiment of the present invention. -
FIG. 2 shows a further process layout according to the invention. -
FIG. 3 shows a schematic diagram of how polystyrene and a solvent such as d-limonene is mixed and filtered prior to heating by a heat exchanger. - Similar reference characters denote corresponding features consistently throughout the attached drawings.
- The invention is directed to an apparatus and method for efficient processing of polystyrene (e.g., expanded or foam polystyrene). The apparatus of the present invention is denoted generally by the
numeric label 100. -
FIG. 1 is a processing flow diagram of apolystyrene processing apparatus 100 according to an embodiment of the present invention. Polystyrene, such as expanded polystyrene, dissolved in solvent is held in resin/solvent tank 120 from which it is directed through aparticle remover 140 to remove solids to provide a substantially solid free solution of polystyrene and solvent. The substantially solid free solution of polystyrene and solvent is thence directed to at least oneheat exchanger 170 by operation of apump 180. Theheat exchanger 170 heats up the substantially solid free solution of polystyrene, which is then directed to sprayer 200. Thesprayer 200 is located inside achamber 220. Thechamber 220 includes aheating jacket 240. At least oneheater 260 is used to provide heated liquid or steam to heatingjacket 240 under the operation of at least onepump 270. - The amount of heat delivered to the
bottom 240 b of theheating jacket 240 should be adjusted to prevent the separated polystyrene polymer from becoming too viscous for efficient plant operation in thebottom part 220 b ofchamber 220. For example, the Applicant has noted that a temperature of about 370° F. maintained in thebottom part 240 b of theheating jacket 240 might be sufficient, but it will be understood by a person or ordinary skill in the art that the temperature of thebottom 240 b of heating jacket 240 (and, therefore 220 b) may vary according to the particular set-up and configuration of thechamber 220 and a person of ordinary skill in the art could establish by routine operation of the plant what temperature should be applied to thebottom 240 b of theheating jacket 240. Likewise, the temperature of in the vicinity of an at least onespray nozzle 205 can be adjusted to ensure that the solution (polystyrene/solvent) is atomized to a sufficient degree to allow for efficient separation of the polymer from the solvent through evaporation ofdroplets 210. A filter, such as glass wool filter 305, can be located at the top ofchamber 220 near anoutput port 310 to prevent strands of styrene carrying over from the styrene-polymer/solvent into theheat exchanger 340. - The
chamber 220 is used to separate the dissolved polystyrene from the solvent. Avacuum pump 320 is used to lower the pressure insidechamber 220. Thevacuum pump 320 can be a liquid ring vacuum pump to allow the solvent to be moved while maintaining a vacuum. Thesprayer 200 generatesdroplets 210 of polystyrene dissolved in solvent, which are directed downward. The solvent evaporates from thedroplets 210 and is drawn upwards by operation ofvacuum pump 320. The solvent is then cooled byheat exchanger 340, then by heat exchanger 350 (with thevacuum pump 320 located betweenheat exchangers 340 and 350). Solvent is collected in asolvent recovery tank 360. - The
chamber 220 is under a vacuum during operation. The vacuum pressure and nozzle pressure can vary and still provide satisfactory operation. More particularly, the vacuum pressure inchamber 220 andnozzle 205 pressure may vary depending based on such factors as heat in the chamber 220 (residual or maintained), GPM or nozzle volume throughput, pressure of produce and laminar flow atnozzles 205, vacuum separation inherent of atomization based on Newton fall. During optimum operation a vacuum of 18″ Hg (eighteen inches Mercury pressure) inchamber 220 should be sufficient to maintain satisfactory operation, but the vacuum pressure inchamber 220 can vary between about 10″ Hg and about 29″ Hg vacuum pressure.Nozzle 205 pressure of about 77 PSI (77 pounds pressure per square inch) should provide satisfactory operation, but the nozzle pressure can vary between about 12 PSI and about 85 PSI. - Recovered solvent held in
tank 360 can be reused to dissolve unprocessed polystyrene. As thedroplets 210 lose solvent, the previously dissolved polystyrene now exists in the form of dense polystyrene polymer. The polymer is optionally agitated by anagitation section 380 prior to exiting at 400. A sufficient amount of heat is delivered to theheating jacket 240 to maintain a temperature of about 370° F. at the bottom of thechamber 220 to prevent the separated styrene polymer from becoming too viscous and difficult to handle. The separated styrene polymer can be converted into pellets by a pelletizer (not shown) as described in U.S. Pat. No. 6,169,121, issued Jan. 2, 2001 to Noguchi et al. - It should be understood that members, such as member 170 (i.e., heat exchanger 170), might comprise a single unit (i.e., one heat exchanger 170) or operate in parallel to increase or meet throughput requirements. Thus, it will be understood by a person of ordinary skill in the art that the process and apparatus shown in
FIG. 1 can vary in number, rated throughput or rearranged (e.g., in units operating in parallel) and still remain within the scope of the claimed invention. - Still referring to
FIG. 1 , aheater 280 is used to provide heat transfer medium to theheat exchanger 170 under the operation ofpump 300. The heat transfer medium can take any suitable form such as liquid or gas (e.g., steam). It will be understood by persons of ordinary skill in the art that the various elements shown inFIG. 1 can be arranged differently without detracting from the spirit of the invention. For example,heaters - The Applicant has devoted a considerable amount of effort into solving the problem of separating polystyrene polymer from resin-solvent solution by means of vacuum spray drying. The resin-solvent solution is extremely viscous and difficult to heat uniformly in a heat exchanger. Polystyrene-solvent ratios of 30/70 (i.e., 30% polystyrene resin concentration) present serious problems in terms of throughput and uniform heating. The resin tends to stick to heat transfer surfaces thereby deleteriously impacting on heat transfer. Resin-solvent ratios of 30/70 are difficult to heat up using, for example, steam heated tube or multiple tube heat exchangers. The resin sticks to the interior surfaces of the tubes thus creating a low heat conducting barrier and thence causing lower throughput due to compromised heat transfer. Resin-solvent ratios of 30/70 will gum up the
sprayer 200 if the resin-solvent is not sufficiently heated. Heating reduces viscosity such that under temperature 30/70 ratio will have too high a viscosity thereby causing gumming up ofsprayer 200. After a considerable amount of effort, the Applicant evolved a solution by proposing spray drying of polystyrene resin/solvent in combination with a heat exchanger upstream of thesprayer 200 and aheating jacket 240 in combination withvacuum pump 320 as shown inFIG. 1 . - Instead of using spray drying under vacuum to separate the solvent from the dissolved polystyrene as taught in the present invention, the prior art teaches applying boiling to separate the solvent from the polystyrene. For example, U.S. Pat. No. 6,169,121 teaches clarifying the solution of polystyrene and solvent by a separator (8) into polystyrene and the solvent. This separator (8) is heated by the thermal medium of a boiler (9) to approximately 240° C. Boiling at such a high temperature is at least partly necessary because the rate of separation of the solvent from the polystyrene is a function of surface area through which the solvent can escape from the polystyrene.
- In the present invention, the Applicant makes use of a
heat exchanger 170 in combination withsprayer 200 andvacuum pump 320, wherein theheat exchanger 170 enables rapid uniform heating of the polystyrene/solvent liquid and thesprayer 200 produces droplets with surface area favorable for more rapid conversion of the solvent into gas and hence speaks to a more rapid separation of polystyrene from the solvent leading to increased throughput of polystyrene/solvent. The combination of sprayer 200 (especially with twister type nozzles, see later) in combination with theheat exchanger 170 enables separation of the polystyrene/solvent mix without boiling the solvent off as required in the prior art '121 patent. Thus, the process of the present invention is far more efficient than that of the prior art as disclosed, for example, in the prior art '121 patent. - It should be understood that the solvent (i.e., processing liquid for dissolving polystyrene such as expanded polystyrene dissolved in a solution of solvent such as d-limonene at, for example, about 30% concentration, i.e., a 30/70 polystyrene/solvent solution, respectively) is not limited to one particular solvent, though limonene and more specifically d-limonene is particularly suited as a solvent for dissolving expanded polystyrene to provide a polystyrene/solvent solution. The solvent can be at least one solvent chosen from a group consisting of an aromatic organic solvent, a hydrocarbon organic solvent, an ether organic solvent, an ester organic solvent, a ketone organic solvent and a monoterpene organic solvent. Also, the solvent can be at least one solvent chosen from the group consisting of limonene, isoamyl acetate, benzyl propionate and ethyl butyrate. In addition, the solvent can be at least one solvent chosen from the group consisting of d-limonene, isoamyl acetate, benzyl propionate and ethyl butyrate. The solvent can be d-limonene.
- The temperature range of operation for the
heat exchanger 170 is typically chosen to deliver the solution (i.e., polymer/solvent) at thesprayer 200 in the range between about 235° F. and 255° F. A person of ordinary skill in the art would monitor the temperature of the solution entering the sprayer and adjust theheater 280 to ensure the temperature of the solution leaving theheat exchanger 170 is high enough to ensure that the temperature of the fluid entering thesprayer 200 is in the range between about 235° F. and 255° F. It is preferred that the solution is not heated above about 350° F. Expanded polystyrene is sometimes pre-treated with a bromine-based fire retardant, which can cause problems if the solution is heated above about 350° F. - The
sprayer 200 should be capable of atomizing the solution to ensure rapid evaporation of the solvent and hence separation of the polystyrene from the solvent. Thesprayer 200 makes use of at least onenozzle 205. Any suitable nozzle can be used so long as the nozzle atomizes the solution, i.e., produces a stream ofdroplets 210 sufficiently small to allow rapid evaporation of the solvent. The at least onenozzle 205 can produce, for example, a hollow coned spray, a full coned spray or a flat spray. The at least onenozzle 205 can be at least one nozzle chosen from a group consisting of a hollow coned spray nozzle, a full coned spray nozzle, a flat spray nozzle, and a twister nozzle. An example of a twister nozzle is the YS series twister nozzle supplied by BEX Incorporated (located at various sites including: 37709 Schoolcraft Road, Livonia, Mich., 48150-1009 USA). BEX Inc. also provides a wide selection of hollow coned, full coned and flat spray nozzles. - Spraying Systems Company also provide a range of spraying system nozzles such as, but not limited to, a full jet, ⅜″, 316SS with a 22 drill (Part # 3/8HH-316SS22). Spraying Systems Company can be contacted at: PO Box 7900, Wheaton Ill. 60189-7900, Phone 630-665-5000. A suitable nozzle type is described in U.S. Pat. No. 3,104,829 issued Sep. 24, 1963 to Wahlin. In addition, Spray Systems Company provides a new range of stainless steel IceJet™ inlet cooling and evaporation nozzles. The IceJet™ inlet cooling and evaporation nozzle utilizes a whirl chamber to produce a fine mist of droplets.
-
FIG. 2 shows a further process layout according to the invention. -
FIG. 3 shows a schematic diagram of how polystyrene and a solvent such as d-limonene is mixed and filtered prior to heating byheat exchanger 170. Example ranges of polystyrene concentration (as volume %) with respect to d-limonene are provided. Specifically, the example range is 1/99 (where the d-limonene solvent contains 1 volume % polystyrene) to 60/40 (where d-limonene solvent contains 60 volume % polystyrene). It will be understood that the exact way of mixing can vary without detracting from the spirit of the claimed invention. - In one non-limiting example (referred to here as “
Example # 1”), the bottom 240 b of theheating jacket 240 is configured to function, at least partly, as a porous heated plate. In this example, theheating jacket 240 is a basic round vessel that is approximately ½ inch thick (variable based on throughput) and has oil circulating in between 2-10 gauge plates at thebottom end 240 b, which is also angled inwards and has, for example, multiple ½ inch openings with oil caused to flow around them. The angle is in relation so that molten polystyrene will flow through into the bottom of the vessel without allowing the mist (originating from droplets 210) to go straight through. The intent of this heated and angledbottom part 240 b with holes is to allow the polystyrene to flatten and thereby increase surface area then flow into the bottom 220 b ofvessel 220. The temperature at the bottom 240 b can be in therange 350° F. to 375° F. The upper part of thechamber 220 is maintained at about 390° F. - Still referring to
Example # 1, the solution (of polystyrene/solvent) enters #22 nozzle at 60-80 psi in (larger than needed 3.4 GPM @1800cP) but there is a possibility of a stringing effect (due to the larger orifice) up to 165° F. in a 70/30 (solvent/polystyrene) ratio and stringing or sporadic effect up to 180° F. due to possible laminar flow and centipoises value of the mass. Hence a spiral incorporated into the at least onenozzle 205 to control momentum diffusion at a specific point and keeping the product temp around 235° F. at the least one spray nozzle 205 (if d-limonene solvent is used, 235° F. is about 15° F. degrees above boiling point of the solvent). Some atomizing effect might be lost because of substance consistency but the height of the vessel and substance velocity should be large enough that any un-flashed solvent will loosen from entrainment through the product/chamber vessel 220 temperature being high enough to create vapor pressure greater than the polymer entrainment ability. Also the Newton force is pulling on the mass (polystyrene) not on the vapor (unless entrained), hence the use of the porousheated section 240 b (any entrained vapor will be released upon impact with 240 b). It is preferred, but not totally necessary, that no more than about 5% of vapors are recovered atblast plate 240 b. It should be understood that the terms “blast base plate 240 b” and “bottom 240 b of theheating jacket 240” are regarded in this embodiment as equivalent terms. - It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the spirit of the invention.
Claims (7)
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US11/458,038 US7592416B2 (en) | 2006-02-16 | 2006-07-17 | Polystyrene processing apparatus and method |
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US11/458,038 US7592416B2 (en) | 2006-02-16 | 2006-07-17 | Polystyrene processing apparatus and method |
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WO2020260774A1 (en) * | 2019-06-28 | 2020-12-30 | Finnfoam Oy | Method for recycling polystyrene and solvent for dissolving polystyrene |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3104829A (en) * | 1962-05-17 | 1963-09-24 | Spraying Systems Co | Vane unit for spray nozzles |
US5824709A (en) * | 1994-11-16 | 1998-10-20 | Suka; Motoshi | Method for recycling waste plastic material containing styrene polymer |
US5863002A (en) * | 1995-10-24 | 1999-01-26 | Sony Corporation | Waste processing apparatus, waste recovery system and liquid container |
US6169121B1 (en) * | 1998-06-18 | 2001-01-02 | Sony Corporation | Method and apparatus for recycling styrene resin |
US6210581B1 (en) * | 1996-07-08 | 2001-04-03 | Sony Corporation | Method of separating flame retardant from plastic composition |
US6500872B1 (en) * | 1999-05-31 | 2002-12-31 | Sony Corporation | Method for recycling waste styrene resin |
US6626235B1 (en) * | 2001-09-28 | 2003-09-30 | Ignas S. Christie | Multi-tube heat exchanger with annular spaces |
-
2006
- 2006-07-17 US US11/458,038 patent/US7592416B2/en active Active - Reinstated
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3104829A (en) * | 1962-05-17 | 1963-09-24 | Spraying Systems Co | Vane unit for spray nozzles |
US5824709A (en) * | 1994-11-16 | 1998-10-20 | Suka; Motoshi | Method for recycling waste plastic material containing styrene polymer |
US5863002A (en) * | 1995-10-24 | 1999-01-26 | Sony Corporation | Waste processing apparatus, waste recovery system and liquid container |
US6098649A (en) * | 1995-10-24 | 2000-08-08 | Sony Corporation | Waste processing apparatus, waste recovery system and liquid container |
US6210581B1 (en) * | 1996-07-08 | 2001-04-03 | Sony Corporation | Method of separating flame retardant from plastic composition |
US6169121B1 (en) * | 1998-06-18 | 2001-01-02 | Sony Corporation | Method and apparatus for recycling styrene resin |
US6500872B1 (en) * | 1999-05-31 | 2002-12-31 | Sony Corporation | Method for recycling waste styrene resin |
US6626235B1 (en) * | 2001-09-28 | 2003-09-30 | Ignas S. Christie | Multi-tube heat exchanger with annular spaces |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2020260774A1 (en) * | 2019-06-28 | 2020-12-30 | Finnfoam Oy | Method for recycling polystyrene and solvent for dissolving polystyrene |
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